Abstract: A cover used in a ventilation fan includes a noise reduction structure and a shelter. The noise reduction structure has an air inlet, a flat portion surrounding the air inlet, and a peripheral portion surrounding the flat portion. The sidewall of the flat portion extends in a vertical direction from the peripheral portion. The bottom surface of the flat portion extends in a horizontal direction from the sidewall, and is a flat surface. The shelter is disposed on the peripheral portion and covers the air inlet.

Abstract: A housing positioning structure includes a housing, an upper supporting structure and a lower supporting structure. The housing includes a top plate and side plates vertically arranged on sides of the top plate. An accommodation space is enclosed by the top plate and the side plates. A horizontal line is formed at the lower edge of the side plate. The direction above and away the horizontal line is defined as an above-body direction, and the direction below and away the horizontal line is defined as a below-body direction. The upper supporting structure is located on the above-body direction side. The lower supporting structure is disposed on the side plates and extends toward the below-body direction side.

Abstract: The present disclosure provides a fixing structure including a base, a first fastener, and a second fastener. The first fastener is disposed on the base and comprises a first hook portion, a first accommodation portion and a first opening portion. The second fastener is disposed on the base and comprises a second hook portion, a second accommodation portion and a second opening portion. A guiding groove is defined by and located between the first and second fasteners and is in communication with the first and second accommodation portions. A positioning channel is defined by the guiding groove, and the first and second accommodation portions, collaboratively. The first and second opening portions are located on the opposite sides of the positioning channel, respectively.

Abstract: A ventilation system includes a ventilation fan with a lamp module, the ventilation fan includes a housing, a base, and a fan module. The base is located below the housing, and the base includes a first flow guiding structure. The fan module is disposed in the housing, and the fan module includes a second flow guiding structure.

Abstract: The present disclosure provides a fixing structure including a base, a first fastener, and a second fastener. The first fastener is disposed on the base and comprises a first hook portion, a first accommodation portion and a first opening portion. The second fastener is disposed on the base and comprises a second hook portion, a second accommodation portion and a second opening portion. A guiding groove is defined by and located between the first and second fasteners and is in communication with the first and second accommodation portions. A positioning channel is defined by the guiding groove, and the first and second accommodation portions, collaboratively. The first and second opening portions are located on the opposite sides of the positioning channel, respectively.